/**
 * Copyright (c) 2013 onionframework.org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 */
package org.onionframework.core.util;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * 反射工具类. copy from springside
 * 
 * 提供调用getter/setter方法, 访问私有变量, 调用私有方法, 获取泛型类型Class, 被AOP过的真实类等工具函数.
 * 
 * @author allan
 */
public class Reflections {
	
    private static final String SETTER_PREFIX = "set";

    private static final String GETTER_PREFIX = "get";

    private static final String CGLIB_CLASS_SEPARATOR = "$$";

    private static Logger logger = LoggerFactory.getLogger(Reflections.class);

    /**
     * 调用Getter方法.
     */
    public static Object invokeGetter(Object obj, String propertyName) {
            String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(propertyName);
            return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {});
    }

    /**
     * 调用Setter方法, 仅匹配方法名。
     */
    public static void invokeSetter(Object obj, String propertyName, Object value) {
            String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(propertyName);
            invokeMethodByName(obj, setterMethodName, new Object[] { value });
    }

    /**
     * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
     */
    public static Object getFieldValue(final Object obj, final String fieldName) {
            Field field = getAccessibleField(obj, fieldName);

            if (field == null) {
                    throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
            }

            Object result = null;
            try {
                    result = field.get(obj);
            } catch (IllegalAccessException e) {
                    logger.error("不可能抛出的异常{}", e.getMessage());
            }
            return result;
    }

    /**
     * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
     */
    public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
            Field field = getAccessibleField(obj, fieldName);

            if (field == null) {
                    throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
            }

            try {
                    field.set(obj, value);
            } catch (IllegalAccessException e) {
                    logger.error("不可能抛出的异常:{}", e.getMessage());
            }
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符.
     * 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用.
     * 同时匹配方法名+参数类型，
     */
    public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,
                    final Object[] args) {
            Method method = getAccessibleMethod(obj, methodName, parameterTypes);
            if (method == null) {
                    throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
            }

            try {
                    return method.invoke(obj, args);
            } catch (Exception e) {
                    throw convertReflectionExceptionToUnchecked(e);
            }
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符，
     * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
     * 只匹配函数名，如果有多个同名函数调用第一个。
     */
    public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
            Method method = getAccessibleMethodByName(obj, methodName);
            if (method == null) {
                    throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
            }

            try {
                    return method.invoke(obj, args);
            } catch (Exception e) {
                    throw convertReflectionExceptionToUnchecked(e);
            }
    }

    /**
     * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.
     * 
     * 如向上转型到Object仍无法找到, 返回null.
     */
    public static Field getAccessibleField(final Object obj, final String fieldName) {
            Field field = getDeclaredField(obj,fieldName);
            makeAccessible(field);
            return field;
    }
    
    public static Field getDeclaredField(final Object obj, final String fieldName) {
        Validate.notNull(obj, "object can't be null");
        Validate.notBlank(fieldName, "fieldName can't be blank");
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
                try {
                        Field field = superClass.getDeclaredField(fieldName);
                        return field;
                } catch (NoSuchFieldException e) {// NOSONAR
                        // Field不在当前类定义,继续向上转型
                }
        }
        return null;
}

    /**
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * 匹配函数名+参数类型。
     * 
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     */
    public static Method getAccessibleMethod(final Object obj, final String methodName,
                    final Class<?>... parameterTypes) {
            Validate.notNull(obj, "object can't be null");
            Validate.notBlank(methodName, "methodName can't be blank");

            for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
                    try {
                            Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
                            makeAccessible(method);
                            return method;
                    } catch (NoSuchMethodException e) {
                            // Method不在当前类定义,继续向上转型
                    }
            }
            return null;
    }

    /**
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * 只匹配函数名。
     * 
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     */
    public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
            Validate.notNull(obj, "object can't be null");
            Validate.notBlank(methodName, "methodName can't be blank");

            for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
                    Method[] methods = searchType.getDeclaredMethods();
                    for (Method method : methods) {
                            if (method.getName().equals(methodName)) {
                                    makeAccessible(method);
                                    return method;
                            }
                    }
            }
            return null;
    }

    /**
     * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     */
    public static void makeAccessible(Method method) {
            if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
                            && !method.isAccessible()) {
                    method.setAccessible(true);
            }
    }

    /**
     * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     */
    public static void makeAccessible(Field field) {
            if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
                            .isFinal(field.getModifiers())) && !field.isAccessible()) {
                    field.setAccessible(true);
            }
    }

    /**
     * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处
     * 如无法找到, 返回Object.class.
     * eg.
     * public UserDao extends HibernateDao<User>
     * 
     * @param clazz The class to introspect
     * @return the first generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
	public static <T> Class<T> getClassGenricType(final Class clazz) {
    	return getGenericType(clazz.getGenericSuperclass(),0);
    }

    /**
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
     * 如无法找到, 返回Object.class.
     * 
     * 如public UserDao extends HibernateDao<User,Long>
     * 
     * @param clazz clazz The class to introspect
     * @param index the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings("rawtypes")
    public static Class getClassGenricType(final Class clazz, final int index) {
         return getGenericType(clazz.getGenericSuperclass(),index);
    }
    
    @SuppressWarnings("rawtypes")
	public static Class getGenericType(Type genType,int index){
		if (!(genType instanceof ParameterizedType)) {
			while(!Object.class.equals(genType) && !(genType instanceof ParameterizedType))
				genType = ((Class)genType).getGenericSuperclass();
			
			if(Object.class.equals(genType))
				return Object.class;
		}

		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

		if (index >= params.length || index < 0) {
			//log.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length);
			return Object.class;
		}
		if (!(params[index] instanceof Class)) {
			//log.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
			return Object.class;
		}
		return (Class) params[index];
	}

    public static Class<?> getUserClass(Object instance) {
            Validate.notNull(instance, "Instance must not be null");
            Class clazz = instance.getClass();
            if ((clazz != null) && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
                    Class<?> superClass = clazz.getSuperclass();
                    if ((superClass != null) && !Object.class.equals(superClass)) {
                            return superClass;
                    }
            }
            return clazz;

    }

    /**
     * 将反射时的checked exception转换为unchecked exception.
     */
    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
            if ((e instanceof IllegalAccessException) || (e instanceof IllegalArgumentException)
                            || (e instanceof NoSuchMethodException)) {
                    return new IllegalArgumentException(e);
            } else if (e instanceof InvocationTargetException) {
                    return new RuntimeException(((InvocationTargetException) e).getTargetException());
            } else if (e instanceof RuntimeException) {
                    return (RuntimeException) e;
            }
            return new RuntimeException("Unexpected Checked Exception.", e);
    }
	        
}
